Legit businesses better take note - I for one won't answer my phone unless I recognize the number because of the now daily spam phone calls I get. Dear business owner, what's the total cost burden to your company if you can't connect with your customers? Write your government representatives and let them know these spam techniques are hurting your business.
Ever since I registered on what appears to be a popular website for college or continuing education information, I started getting these calls. Be cautious who you give your number to or anticipate stupid spam calls to follow.
I too am on some kind of a list because every day I get calls from random numbers. This one called today. So, I did what I've been doing to all of them: I picked up the phone, pressed PLAY on this sound file:
http://artofhacking.com/files/sounds/live/aoh_sit-vc.htm
And hung up. It seems to be working, so far the numbers I use it on don't call back. But, I'm sure the list I'm on is sent to DOZENS of scammers and telemarketers, so it will probably be a while until these calls completely stop. Your best bet is to put in fake phone numbers for anything you sign up for online.